The US stock market has been in a long-term bull run, yet most individual investors still lose money. The core reasons are the combined effects of five factors: indices ≠ individual stocks, human weaknesses, institutional dominance, costs and leverage, and failed market timing.

1. Index Gains ≠ Gains in Your Stocks

- Indices are driven by a few leading stocks: The S&P 500 and Nasdaq 100 are powered by a handful of heavyweights like Apple, Microsoft, and NVIDIA; 80% of individual stocks underperform the indices, with many small-cap and thematic stocks experiencing prolonged declines or even delisting.

- Retail investors love speculating on small caps/themes: They favor highly volatile, high-turnover junk stocks and concept stocks, perfectly avoiding the leading gainers.

2. Human Weaknesses: Chasing Rallies + Panic Selling + Inability to Hold

- Buying high, selling low: Jumping in at the peak of a bull market, then panic selling after a 10%-20% pullback; perfectly missing the main uptrend and only catching the last leg.

- Inability to hold: The US market averages a 10%+ correction every 2.5 years and a bear market every 6 years; 95% of retail investors can't withstand the volatility, selling at the bottom and chasing highs at the top.

- Overtrading: Retail annual turnover often exceeds 500%, with commissions, taxes, and slippage eating up 8%-15% of returns; a 10% index gain might still result in a loss after costs.

3. Institutional Dominance: Retail Has No Edge

- Information gap: Institutions have research reports, data, insider access, and quantitative models; retail relies on rumors, charts, and emotions.

- Capital gap: Institutions can hold long-term, position early, diversify, and hedge; retail has limited capital, often goes all-in on single stocks, and chases rallies.

- Speed gap: High-frequency trading executes in milliseconds; manual retail orders get repeatedly "shaken out."

4. Leverage & Costs: The Deadly Amplifiers

- Leverage blow-ups: Margin accounts, options, and leverage amplify gains in a bull market but lead to forced liquidation and total loss during a pullback.

- Hidden costs: US stock commissions, capital gains taxes, currency exchange losses, and fund management fees significantly erode long-term compound returns.

5. Market Timing is a Loser's Game: Missing Key Gain Days

- 90% of the S&P 500's gains come from the best 10-20 days of the year; missing just those days drastically underperforms or even leads to long-term losses.

- Precise timing is nearly impossible. Most people "buy high and sell low," with their returns reduced by 3%-5% due to the "behavior gap."

How Can Ordinary People Break the Cycle (Simplified Version)

- Give up stock picking, buy broad-based indices: SPY, VOO, $Invesco QQQ Trust(QQQ.US), and hold long-term.

- Dollar-cost averaging + no timing: Invest a fixed amount monthly, ignore volatility, smooth out costs.

- Low turnover + no leverage: Annual turnover <20%, no margin, avoid options.

- Diversify + long-term: No single stock over 10% of portfolio, hold for 5+ years, benefit from compounding.